The background description provided herein is for the purpose of generally presenting the context of the present invention and is neither expressly nor impliedly admitted as prior art against the present invention. The subject matter discussed in the background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art. The subject matter in the background of the invention section merely represents different approaches, which in and of themselves may also be inventions.
U.S. Patent Application Publication No. 20140054155 discloses a dome-shaped movable contact piece with a long stroke, that is, a long indentation amount, of a switch of an input operation part of a keyboard of a portable phone or an electronic device. The movable contact piece includes a dome-shaped contact piece arching upward. The dome-shaped contact piece is provided with four substantially triangular notches that are located between a central portion of the dome-shaped contact piece and a peripheral portion of the dome-shaped contact piece. Chamfering corner portions or vertex angle portions of the notches may prevent a crack from being generated on the dome-shaped contact piece. However, it should be noted that four notches are formed on the dome-shaped contact piece, and accordingly, four connection portions are formed. When the dome-shaped contact piece is subjected to a pressure and is elastically deformed, the four connection portions are subjected to partial contraction and partial expansion. When the dome-shaped contact piece is repeatedly pressed for multiple times, the four connection portions are subjected to repeated partial contraction and partial expansion, and cracks may easily occur on side walls (that is, the side walls of the notches), particularly in positions subjected to the partial expansion.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.